Leak reports collect information about the last uptrend

components/metrics/leak_detector/leak_detector_impl.h

Index: components/metrics/leak_detector/leak_detector_impl.h
diff --git a/components/metrics/leak_detector/leak_detector_impl.h b/components/metrics/leak_detector/leak_detector_impl.h
index bf6a58e60165d32369491148b8145a26732cb38e..91f00d9ad3be05803f98bfc357ca39ac3ec5e354 100644
--- a/components/metrics/leak_detector/leak_detector_impl.h
+++ b/components/metrics/leak_detector/leak_detector_impl.h
@@ -67,6 +67,15 @@ class LeakDetectorImpl {
       return alloc_breakdown_history_;
     }
 
+    size_t num_rising_intervals() const { return num_rising_intervals_; }
+
+    uint32_t num_allocs_increase() const { return num_allocs_increase_; }
+
+    // Transform number of allocation events into number of analysis intervals.
+    void normalize_num_rising_intervals(size_t timeslot_size) {

[Simon Que, 2016/10/11 01:11:06]

This is a bad design pattern because you could call this multiple times and it
will make this division multiple times.

I suggest using accessor/mutator for |num_rising_intervals|.

[mwlodar, 2016/10/11 07:13:24]

Done.

+      num_rising_intervals_ /= timeslot_size;
+    }
+
     // Used to compare the contents of two leak reports.
     bool operator<(const LeakReport& other) const;
 
@@ -78,6 +87,12 @@ class LeakDetectorImpl {
     // Number of bytes allocated by the leak site during each allocation.
     size_t alloc_size_bytes_;
 
+    // Number of intervals in the last uptrend.
+    size_t num_rising_intervals_;
+
+    // Net number of bytes allocated in the last uptrend.
+    uint32_t num_allocs_increase_;
+
     // Unlike the CallStack struct, which consists of addresses, this call stack
     // will contain offsets in the executable binary.
     InternalVector<uintptr_t> call_stack_;
@@ -105,7 +120,7 @@ class LeakDetectorImpl {
   void RecordFree(const void* ptr);
 
   // Run check for possible leaks based on the current profiling data.
-  void TestForLeaks(InternalVector<LeakReport>* reports);
+  void TestForLeaks(InternalVector<LeakReport>* reports, size_t timestamp);

[Simon Que, 2016/10/11 01:11:06]

Explain the role of |timestamp| in the comments.

[mwlodar, 2016/10/11 07:13:24]

I have added comments below.

 
  private:
   // A record of allocations for a particular size.
@@ -164,13 +179,13 @@ class LeakDetectorImpl {
   // Not all the net alloc counts are recorded. And the number of historical
   // records kept is capped. If adding a new record exceeds that limit, the
   // oldest record is discarded. See the function definition for more details.
-  void RecordCurrentAllocationDataInHistory();
+  void RecordCurrentAllocationDataInHistory(size_t timestamp);
 
   // Store the data collected by RecordCurrentAllocationDataInHistory() in
   // |*report|. Not all net alloc counts per call site will be stored, only the
   // count for size=|size| and made from |call_site|.
   void StoreHistoricalDataInReport(size_t size, const CallStack* call_site,
-                                   LeakReport* report);
+                                   LeakReport* report, size_t timestamp);
 
   // Decrements the cooldown counter (value) for each entry in
   // |cooldowns_per_leak_|. If the cooldown counter reaches 0, the entry is